I don't remember the first wiki I ever stumbled upon, but I do remember the first wiki I edited.
On September 15, 2006, my favorite-amazingly-awesome-Internet-Indie Rock radio station, WOXY, went dark. Incredibly depressed, I logged onto their Wikipedia page and edited it to add a list of the final three songs the DJs played before silence. Songs by Oasis, Public Enemy, MC5...
WOXY has since returned, having risen Phoenix-like from the ashes after being saved by a kind-hearted business person. And I've noticed that people have edited the page, removing my edits, and have added all sorts of new information.
This is the beauty of wikis. They are collaborative and social and anyone can edit them. I think it's very difficult to add wrong information. There are too many hardcore wiki editors out there who will swoop in and make things right. And another beauty is, wikis can revert to their previous state before edits. So if anyone completely destroys a wiki, you can time travel back to before the destruction.
So wikis can be fun. I just edited the Neflin 23 Things wiki to add that I think peanut butter wikis are yummy.